In large industrial or utility motors and generators, the stator windings, also known as armature windings, can include a series of stator windings. Each stator winding can include a series of conductive or stator bars wrapped in one or more layers of insulation. The insulation can confine the current in the stator bars, and can prevent the arcing of electrical current between windings. Furthermore, the insulation can shield the stator bars against stray objects that could electrically short the bars. If the insulating properties of the insulation degrades over time or becomes damp due to excess moisture from a cooling leak, voltage arcs may jump from the stator bars through degraded regions of the insulation and cause electrical shorts that may harm people and/or equipment. Early detection of such leaks can minimize or prevent harm to people and/or equipment.
Various maps of the stator windings, in particular, the stator bar insulation, can be created to track and monitor different physical characteristics, such as temperature or other physical characteristics. These maps can assist an operator or testing personnel in identifying failures or defects in the stator windings or stator bars. As described above, the failure to detect moisture in the stator windings and stator bards can lead to dangerous electrical shorts, such as “phase to ground faults” or “phase to phase faults”.
One type of map that can be generated during a generator service inspection is a “capacitance map”. A capacitance map can include a display of capacitance measurements of each of the stator bars. In this example, each capacitance measurement can be measured at two locations along the stator bar, with one measurement at each end of the generator. Typically, statistical analysis of the collected data can be conducted during or after data collection to filter outlier-type or false negative data based on a predetermined standard. However, data collection using conventional techniques and devices may be prone to error. Using a conventional probe to measure capacitance, the conventional probe can be mounted to a stator bar wherein the probe is in physical contact with the stator bar. In some instances, variations or imperfections in the surface area of the probe can cause noise in the capacitance measurements. In some other instances, gaps between the probe and the surface of the stator bar or insulated stator bar can cause noise in the capacitance measurements. In other instances, probe misalignment can cause noise in the capacitance measurements. In any instance, noise in the capacitance measurements can affect the quality of the collected data.
Thus, there is a need for improved stator monitoring systems and methods. There is also a need for systems, methods, and apparatus to collect capacitance data from a stator component. There is also a need for systems, methods, and apparatus for measuring capacitance in a stator component.